1. Field of the Invention
The present invention relates to novel compounds comprising a dihydropyridine basic nucleus and bearing substituted piperidyl substituents.
This invention also relates to the use of such novel compounds for the heat and light stabilization of polymers.
2. Description of the Prior Art
FR-A-2,239,496 describes 2,6-dimethyl-3,5-dicarboxylate-1,4-dihydropyridines as heat stabilizers for polyvinyl chloride (PVC).
EP-A-0,005,678 describes the synergistic effect between 2,6-dimethyl-3,5-dicarboxylate-1,4-dihydropyridines and .beta.-diketones for the heat stabilization of PVC.
These 1,4-dihydropyridine compounds are effective heat stabilizers for PVC. However, they are insufficient for certain applications where the polymer is subjected to external exposures, namely, in the event that the polymer must also have a stability to light.